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Wall mounting cast iron radiator -- Height question

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JudyW
JudyW Member Posts: 16

I was wondering if there's any rules or caveats regarding how high up on a wall can one mount a cast iron radiator? I have a one-pipe steam system, and all rads are 2 column, 7" wide, 38" high (so that's what's in the first pic, behind the vanity). I'm having a bathroom remodel done, and would like too relocate where the rad is. It's in an awkward spot and you can't get to the valve if you wanted to without removing the vanity. I'd like to get a 3" wide Mercury from Castrads and mount it on the wall above where the current rad is, above the top of the 4ft tile wainscot that's going in. I hope the terrible scribbled pic gives a good enough idea of what I mean. It's an outside facing wall, and it's brick, so I'm guessing the weight won't be an issue. Castrads makes wall mount brackets for this model, but in every pic I've seen of wall-mounted radiators, they're still quite low to the floor. I'm just wondering if mounting 4+ft up will have me ending up with a bathroom that's cold up to my chest, or will the warmth circulate down enough. I have 9' ceilings, if that matters at all. Sorry about the blurry pics. I had to zoom & crop, so crappy resolution.

1000019419.jpg 1000019426.jpg

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 26,991

    Won't hurt the radiator any — it will work just fine up there. Now… yo won't get much warm air down around your feet and ankles, though… maybe a fan to circulate?

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    mattmia2
  • mattmia2
    mattmia2 Member Posts: 15,980
    edited January 24

    and getting it there won't be fun.

    btw the vent should be about 2/3 down on the end opposite your supply, that is the tapping for a steam air vent. the tapping at the top is for a hot water bleeder.

    depending on the extent of the renovation you might want to but a little bit of electric radiant in the floor just to make it warm

    dabrakeman
  • hot_rod
    hot_rod Member Posts: 27,052

    with copper fin tube emitters, the higher up off the flow, the lower the output. This is mainly due to convection currents as the incoming air temperature is increased the higher they are mounted.

    SlantFin actually has or had a derate chart for that correction

    A cast rad transfers by both radiation and convection I don’t know the %
    So my thought is you will lose a small % of heat output the higher you mount them

    Radiation is line of site so maybe the higher it mounts the less of your body it sees?

    Fin tube in enclosure is more convection than radiation

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • mattmia2
    mattmia2 Member Posts: 15,980

    i would think your body would see more of the radiator off the floor than half way behind the vanity

    EdTheHeaterMan
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 11,747

    It's a bathroom, not a rocket surgery project. Get a wall radiator that closely matches the EDR of the one you are removing and mount if on the wall above the vanity. Then the renovation vanity can be made to go completely to the wall. Put the inlet valve close to the bottom with a proper pitch (one pipe steam)for condensate to flow back to the inlet. Then get the vent tapping to be a little closer to the bottom 1/3 of the radiator in order to get more steam in there. Your may even like a fancy Towel Warmer as the radiator. That hot towel getting out of the shower in the winter will make up for the slightly lower floor temperature.

    Screenshot 2026-01-25 at 9.13.13 PM.png

    Location A can be drilled and tapped for a better vent location on this towel warmer made for a hot water system.

    Location B can be modified with a chrome elbow fitting for a one pipe steam system

    I'm sure that radiator is a lot more expensive that the one you were looking at from Cast Rads.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?